GPT Image 2.5 vs Nano Banana 2: Specs and Use Cases

GPT Image 2.5 and Nano Banana 2 differ most in output shapes, prompt and reference limits, provenance signals and how their APIs bill. OpenAI splits GPT Image 2.5 into a fast tier (Flare) and a precision tier (Sunburst). Google now steers new projects to Nano Banana 2.1 instead of Nano Banana 2. This is a spec and positioning comparison only. No side-by-side quality tests were run, so it does not rank which model makes better-looking images.

Key Takeaways

• Pick GPT Image 2.5 Flare for fast everyday generation and Sunburst for precise, multi-step edits. OpenAI charges the same API price for both.
• Google recommends Nano Banana 2.1 for all new projects. Nano Banana 2 is now its previous-generation model, and Nano Banana Pro is its reasoning-driven option.
• On VerseIn, GPT Image 2.5 accepts much longer prompts, while Nano Banana 2.1 offers the widest range of aspect ratios, including very tall and very wide formats.
• OpenAI bills GPT Image 2.5 by tokens and publishes no per-image price, so a fair per-image cost comparison with Nano Banana isn't possible from public docs.

Meet the two model families

Both vendors now offer more than one model under the same name, so it helps to know which version you're actually choosing.

GPT Image 2.5: Flare and Sunburst

OpenAI published both tiers as snapshots dated September 8, 2026. The Flare model page calls it "our fastest model for high-quality, everyday image generation," while the Sunburst model page calls it the "most capable model for image generation and editing." OpenAI's current image generation guide lists both for the Image API and the Responses API image generation tool, and puts the positioning split simply: "Choose Sunburst for workflows where editing precision matters most."

OpenAI's announcement describes Flare as the "default choice for most applications," with higher quality than GPT-Image-2 at 50% lower latency. That's OpenAI's own claim, not an independent benchmark. The announcement describes Sunburst as "built for premium visual workflows that benefit from tighter control across edits," with longer generation times. For a closer look at the two tiers, see GPT Image 2.5 Flare vs Sunburst.

Nano Banana 2, 2.1 and Pro

Nano Banana 2 (gemini-3.1-flash-image) launched on February 26, 2026 as a way to bring Pro-level capabilities to a faster model. Google's model docs now call it the "previous-generation workhorse."

Nano Banana 2.1 became generally available on October 6, 2026. Google describes it as offering "Flash-level speed and cost" and states: "Recommended for all new projects to use Nano Banana 2.1." Nano Banana Pro is Google's "reasoning-driven engine for professional-grade image editing and generation."

In the Gemini app, free users get Nano Banana 2, while Google AI Plus, Pro and Ultra subscribers get Nano Banana 2.1. Paid plans can also "Redo with Pro."

Spec comparison at a glance

The VerseIn rows reflect each model's page on VerseIn. The native size row reflects the vendor docs linked above.

VerseIn pages: GPT Image 2.5 Flare, GPT Image 2.5 Sunburst, Nano Banana 2, Nano Banana 2.1 and Nano Banana Pro.

Output size and aspect ratio

Every one of these models offers a 1K, 2K or 4K selector on VerseIn, so the real difference is the shape of the frame.

GPT Image 2.5's API accepts custom pixel sizes (multiples of 16, 1:3 to 3:1, up to 3840 px), per OpenAI's image generation guide. The Nano Banana docs cited here list fixed 1K/2K/4K resolutions. OpenAI labels sizes above 2560x1440 "experimental," so plan on the largest outputs being less predictable.

Nano Banana 2.1 covers the extremes. Of the ratio lists VerseIn shows (Pro's 8 aren't itemized), only Nano Banana 2.1 includes 4:5, 5:4, 1:8 and 8:1. The 1:8 and 8:1 shapes suit tall scrolling graphics or thin website banners, and 4:5 is a common portrait feed format. GPT Image 2.5's list on VerseIn has its own unusual options, such as 27:16 and 9:8, but no 4:5.

Reference images and editing

For reference-heavy work, Sunburst and Nano Banana 2.1 have the highest reference counts listed on VerseIn.

On the OpenAI side, inpainting is supported, and OpenAI positions Sunburst for tighter control across edits. VerseIn describes Sunburst as holding up across references. Flare on VerseIn lets you reuse saved characters as references, which helps when the same person or mascot appears in a series.

On the Google side, the Nano Banana 2 launch post describes up to 5 characters and 14 objects per workflow. VerseIn describes Nano Banana 2.1 as offering sharp text, consistent subjects across edits and mask-based control. Those are VerseIn's descriptions, not test results.

OpenAI also publishes its own list of known limitations. Complex prompts can take up to about 2 minutes. Text rendering, character consistency and precise layout can still be weak, and when you send multiple input images, the mask applies only to the first one. The Google pages cited here don't carry a comparable list, which doesn't mean those issues never occur.

Prompt length

GPT Image 2.5 gives you about four times the prompt room on VerseIn. That matters if your prompts carry brand rules, shot lists or multi-part instructions, and VerseIn describes Sunburst as following complex multi-part instructions. With any Nano Banana model, long briefs need trimming to fit, so lead with the details that matter most.

Watermarking and provenance

Both vendors mark AI-generated images, though the signals differ.

• OpenAI: The GPT Image 2.5 announcement describes C2PA metadata plus invisible watermarking.
• Google: Images from the Gemini API include a SynthID watermark. The Gemini app adds a visible watermark too. Nano Banana 2.1 also supports C2PA Content Credentials, per its model page.

If your clients or platforms ask for C2PA provenance, GPT Image 2.5 and Nano Banana 2.1 both document it.

How API pricing works

The two vendors use different billing units, so their prices can't be lined up per image.

OpenAI lists the same rates for Flare and Sunburst. Text input costs $5 per 1M tokens and image input $8 per 1M tokens. Image output costs $30 per 1M tokens, or $15 with Batch. OpenAI publishes no per-image price for GPT Image 2.5.

Google's pricing page lists per-image prices:

Image output tokens cost $30 per 1M for Nano Banana 2.1 and $60 per 1M for Nano Banana 2. Within Google's lineup, 2.1 costs less than 2 at every listed size.

On VerseIn, you pay in credits instead. The amount depends on the tool, model and settings, and you always see the total cost before you confirm. If a generation fails because of a processing error, timeout or content safety check, the credits are returned automatically.

Which one to choose by job

These are suggestions based on vendor positioning and published specs. Run your own prompts through both before you commit to one for a project.

• Fast drafts and quick iteration: GPT Image 2.5 Flare or Nano Banana 2.1. Both are positioned for speed.
• Precise edits over several rounds: GPT Image 2.5 Sunburst, the tier OpenAI recommends when editing precision matters most.
• Long, structured prompts: GPT Image 2.5 currently shows the larger prompt allowance on VerseIn; check the live counter before relying on an exact limit.
• Many reference images: Sunburst or Nano Banana 2.1, the two with the highest reference counts listed on VerseIn.
• 4:5 feed posts, tall graphics or thin banners: Nano Banana 2.1, the only model here whose VerseIn ratio list includes 4:5, 1:8 and 8:1.
• Transparent backgrounds: GPT Image 2.5. OpenAI documents transparent backgrounds with png or webp output.
• Starting a new project on Google's models: Nano Banana 2.1, as Google recommends. Try Nano Banana Pro when the job is a complex layout; VerseIn describes it as "Ultra-HD multi-object layouts."

For a wider view of the options, see the best AI image generators. If GPT Image 2.5 is new to you, start with What Is GPT Image 2.5?

FAQ

Is GPT Image 2.5 better than Nano Banana 2?

Neither is better across the board. GPT Image 2.5 leads on prompt length. Its API also accepts custom pixel sizes (multiples of 16, 1:3 to 3:1, up to 3840 px). The Nano Banana docs cited here list fixed 1K/2K/4K resolutions. Nano Banana 2.1, Google's recommended successor to Nano Banana 2, leads on aspect ratio range. Image quality wasn't tested here, so compare outputs on your own prompts.

Should I use Nano Banana 2 or Nano Banana 2.1?

For new work, Google recommends Nano Banana 2.1. It supports more aspect ratios on VerseIn and costs less per image in Google's API. Nano Banana 2 still works, but Google now treats it as the previous generation.

Which is cheaper, GPT Image 2.5 or Nano Banana?

There's no fair per-image answer from public pricing, because OpenAI bills GPT Image 2.5 by tokens and publishes no per-image figure. On VerseIn, each model shows its credit cost before you confirm, so you can compare there for your exact settings.

Can I use both models on VerseIn?

Yes. GPT Image 2.5 Flare and Sunburst, Nano Banana 2, Nano Banana 2.1 and Nano Banana Pro each have their own model page on VerseIn for text-to-image and image-to-image work. New accounts get free sign-up credits, and results are saved to your Media library.